# physics

posted by .

A person jumps from the roof of a house 4.0- high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.74. 1)If the mass of his torso (excluding legs) is 40 , find his velocity just before his feet strike the ground. 2)If the mass of his torso (excluding legs) is 40 , find the magnitude of the average force exerted on his torso by his legs during deceleration.

• physics -

mgh=1/2 m v^2
v=sqrt 4*g

2) force*distance=1/2 m v^2
force= mass*(4g)/2d= 2*g*mass/.74

check that.

• physics -

I don't understand this part....

2) force*distance=1/2 m v^2
force= mass*(4g)/2d= 2*g*mass/.74

## Similar Questions

1. ### AP Physics

A person jumps from the roof of a house 3.0 m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.60 m. The mass of his torso (excluding legs) is 48 kg. *How do …
2. ### Physics question

Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced a force of approximately 260,000 N acting on its torso when it hit the ground. Question 1 Assuming the torso has a mass of 3800 kg …
3. ### PHYSICS PLZ HELP =-(

Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced a force of approximately 260,000 N acting on its torso when it hit the ground. Question 1 Assuming the torso has a mass of 3800 kg …
4. ### Physics Problem

Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced a force of approximately 260,000 N acting on its torso when it hit the ground. Question 1 Assuming the torso has a mass of 3800 kg …
5. ### Ap Physics

Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced a force of approximately 260,000N acting on its torso when it hit the ground. Assuming the torso has a mass of 3800kg , find the …
6. ### Physics

Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced an upward normal force of approximately 261,100 N acting on its torso when it hit the ground. Assume the torso has a mass of 3700 …
7. ### physics

A person jumps from the roof of a house 3.6 -m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70 {\rm m}. If the mass of his torso (excluding legs) is 46 kg. …
8. ### physics

A person jumps from the roof of a house 4.9 m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70 m. The mass of his torso (excluding legs) is 46 kg. (a) Find …
9. ### Physics

A person jumps from a tower 5 m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70m. If the mass of his torso (excluding legs) is 50kg, find the force exerted …
10. ### physics

A person jumps from the roof of a house 4.0-m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.66m. If the mass of his torso (excluding legs) is 42kg , what …

More Similar Questions